Fraga



Dec. 29, 1964 A FRAGA DAMPER CONTROL MECHANISM Filed Dec. 20, 1962 United States Patent Ofifice BJhBJZ Patented Dec. 29, 1964 3,163,102 DAMPER CONTROL MECHANISM Anthony Fraga, Brooklyn, N.Y., assignor to Slant/ Fin Radiator Corporation, Richmond Hill, N.Y., a corporation of New York Filed Dec. 20, 1962, Ser. No. 246,114 7 Claims. (Ci. 98-106) An object of this invention resides in novel means for control or adjustable positioning of dampers, more specifically in novel control means for radiator dampers which, in use, is subjected to a wide range of temperatures.

A common form of radiator damper involves a horizontally hinged elongated damper that can be moved to various relatively open or closed positions by a manually operated damper control rod. In that form of radiator damper, the control rod has a helical drive element on a shaft in the radiator enclosure that cooperates with a slot in a sheet-metal part of the damper. The weight of the damper is often considerable. As a consequence, when the damper has been raised to an adjusted opening and the knob of the damper control rod is released, the helical control rod of the damper is caused to spin by the weight of the damper as the damper dropsout of its adjusted position. Further, the helical control rod is sometimes unknowingly forced after the damper (normally concealed within the radiator housing) has reached a limiting extreme position. The cooperating portions of the helical control rod and the slot in the damper are then stripped or deformed out of efiective mating contact.

Accordingly, a further object of the invention resides in the provision of a novel damper control that is largely, if not wholly, immune to the foregoing defects.

In carrying out the foregoing objects, a preferred embodiment of the invention has been produced which includes a control rod rotatably mounted in the enclosure for cooperation with a portion of the damper. The control rod in this embodiment is formed of a bar or strip of metal that is twisted so as to have two opposite helical edges. This rod works in a slot in a plastic part carried by the damper. If the damper is blocked at either extreme of its adjustment range, the shaft could still be 'forced without damaging its cooperating plastic part.

Furthermore, the plastic part and the helical rod are in tight gripping contact so that the controlrod is gripped at all times and prevented from self-rotation due to the weight of the damper. This result is achieved without resort to close tolerances or supplemental frictional structures.

The nature of the invention, together with the above and further objects and features of novelty, will be more fully appreciated from the following description of the presently preferred but illustrative embodiment which is shown in the accompanying drawings forming part of this disclosure. In the drawings:

FIGURE 1 is a perspective view of an embodiment of the invention, parts cross-section;

FIGURE 2 is a vertical cross-sectional view of the embodiment in FIGURE 1, drawing to much larger scale;

FIGURE 3 is a rear elevation of a portion of the damper in FIGURES 1 and 2; and i being broken away and shown in FIGURE 4 is an enlarged detail, partly in section, of a portion of FIGURES 1 and 2.

Referring now to the drawings, there is shown the top portion of a radiator housing, including a top panel 10 and a front panel 12. A damper 14 is supported on a hinge 16 near the top of panel 12. A large number of louvers 18 of conventional form are provided in the front panel 12, this panel being slit longitudinally and the slit elements being bent out of the plane of the front panel.

Within enclosure 10, 12 and ordinarily below damper 14 and louvers 18 is a radiator unit (not shown) that provides an apertured area for a rising current of heated air. This air current can emerge from louvers 18, but only if damper 14 is open. The maximum opening is represented by the dotted-line position 14' in FIGURE 2. Position 14' is reached when the damper strikes the rear of the enclosure or any other stop means (not shown). When the damper is closed, the flow of hot air is blocked.

For the purpose of adjusting the degree of opening of damper 14, the following improved mechanism is provided.

To the rear of damper 14, there is secured a three-part assembly including a sheet of plastic 29 that is confined between two metal frame members 22 and 24. These metal members overlie the marginal portions of members 20, and they extend laterally outward of the edges of plastic element 20. They are welded together, and further they are secured by a suitable means (not shown) to damper 14. Member 24 includes a raised formation which provides a sort of pocket that accommodates the thickness of plastic element 20 and locates that element against lateral shift, either vertically or horizontally, relative to the face of damper 14.

Element 26 has a slit Zita that is quite long and relatively narrow. Member 22 has an opening 22a that is larger in both directions than slit 29a. correspondingly,

. element 24 has an opening 24a behind element 20 and framed about slit 20a.

A damper control rod 26 penetrates opening 20a of plastic member 20. Control rod 26 is made of an initially fiat strip or bar of metal that is twisted into a double-edged helix, which may be called a twist operator. As seen in FIGURE 3, the rod 26 that was an initially flat strip retains relatively wide surfaces after the strip is twisted, and the edges of the strip become helical edges. A highly effective helical pitch is illustrated, in which a l-degree twist measured along the rod is a little larger than the maximum transverse dimension of the rod. Rod 26 is mounted rotatably in an internally threaded piece 28 that is welded to panel 12. Externally threaded bushing 29 extends through panel 12 and into piece 28. Shaft 26 has a necked-down end portion 26a that extends rotatably through bushing 29 and into knob 30, where it is locked as by means of a conventional set screw.

The thickness of rod 26 is approximately equal to the width of slit 28a. The edges of the slit Ztla grip and squeeze against the helically contoured opposite wide faces of damper control rod 26. The adjoining portions of plastic element 20 are deformed somewhat by the helical or twisted shape of member 26. Because of this relationship, there is a tight binding grip that is exerted on shaft 26 by member 20.

Slit 20a is long enough so that shaft 26 is received in that slit in both of the extreme positions 14 and 14- to which the damper can be adjusted. When the damper is in its solid-line position of FIGURE 2, the helical rod the adjustment force-'fromirod 26 to the damper. firmness of plastic member 20 is enhanced through most so as to act in the manner described above.

r 3 either of 'theeirtremepositionsillustrated in FIGURE 2 to-the otherand toany intermediate'position.

When the damper has reached either extreme condition of its adjustment, it is possible that the person who is operating the damper might not realize this'fact and he helical wire in the prior arrangement. After that had occurred, the reversecperation of the knob, particularlyin attempting to move the damper from its vertical, depending position-to a raised position, would he ineffectual.

When either extremeposition of adjustment has been reached with the novel damper control arrangement described above andshown in the drawings, the edges of plastic memberwwvill be hearing against the wide faces of rod 26,as 'in'FIGURES. Continued, forcible operation'of rod'26 after the damper has reached a li'mitQWill result in. portions of member-2t) being pushed or pulled out of their normal plane by the broad surfaces of twisted rod 26. Asa full'half-turn of rod 26' beyond the damper -limit is reached, theplastic resiliently resumes the configuration in FIGURES. 'ble drive of the control rod beyond the point Where the No damage results from forcidamper has reached a limiting position. Thereaften'reverse rotation of the damper control rod is fullyeffective in adjusting the damper away from that limiting position, just as if forced operation beyond the limit had not taken place.

Damper I4- is often arelatively heavy member, for it -'may bewell overa'yard long and it is made of relatively heavy-gauge sheet metal. "In comparable apparatus that *uses the above-mentioned known form of helical control rod working in a slot in the damper, the weight of the damperis" such that there has'beena strong tendencyof the damper to drop from" any open condition of adjustment toward its fully closed position, when the adjustment knob is released. Thedampenweightsimply causes the control rodto spin as 'thedamper drops. The firm grip of the plasticelernent 20 with the described damper control rod 26"is highly effective in holding the damper hired in any position'ofadjustm'ent'to'vvhich it is moved,

"Member '20 is madeadequa'tely' thick for transmitting The of the-adjustment rangeby limiting thewidth of the slots 22a'and 24a, as illustrated. Thewidth of these openings is increased near the'end limits so that rod- 26 can be forced (whileme'mb"ers' 14- and" 20are arrested) Without damaging member 29.

Member 24) is of suitable'pla'stic that is yieldable As part of a radiator dampenit-is' of a plastic that retains its'pliable,

firm and resilient properties over a wide range. Polyurethanehas been found to 'be particularly 'eiiective for this purpose. Furthermore, polyurethane'isnonfabrasive. From the foregoing, it willbe seen that a highly-successful embodiment of the" present invention has been dehaving an apertured area, a damper hinged to the rear of said panel adapted to cover said apertured area and operable through an angle between open and clos'edlirnits,

a damper control rod'having opposite wide surfaces bounded by helical longitudinal edges, means supporting said rod for rotation about a fixed axis, said supporting -means being carried by said front panel, said-meansalso constraining the rod against axial shift relative to said front panel, and a memberof tough and resilient plastic material fixed to said damper and formed with an elongated slot generally perpendicular to the axis of the hinged damper, the-slot insaid plastic member receiving said damper control rod and the edges of the slot gripping said opposite Wide surfaces of the control rod, andmeans to rotate said control rod.

2. In combination an enclosurehaving a front panel having an apertured area, a damper hinged to the rear of said, panel adapted to cover said apertured areaand operable through a range between open and closed limits, a damper control rod having opposite wide surfaces bounded by a pair of opposite helical longitudinal edges, means supporting said rod for rotation about afixed axis, said supporting means being carried by said front panel said means also constraining the'rod against axial shift relative to said front panel, and means secured to said damper for cooperating Withsaid damper control rod, said means includinga frame member having an opening therein, a member of tough and resilient plastic material supported by said' frame member on-said damper and formed with an elongated slot generally perpendicular to the axis of the hingeddamper, the" slot iii-said plastic member receiving said damper control rod and the edges of theslot gripping said opposite wide surfaces of=the control rod, the opening in said frame-member beingonly a little wider than'said slot and said frame member bearing against the surface of'said plastic member outsidesaid opening and thereby'reinforcingsaid plastic member adj acentthe slot, and means-to rotate said control rod.

3. The combination in'accordance with claim. 1 above, wherein said plastic member is a sheet of polyurethane.

4. The combination in accordance with claim 1 wherein the-width of saidwide surfacm is a little smallerthan'onehalf of the helical pitch of said longitudinal edges 'of'the rod, and whereinsaidplastic member is asheet disposed "transverse of said rod and the thickness of the'plastic sheet being only a small part of-said one-half helical pitch.

5. In combination anenclosure having a nlouvered panel, a damper panel mounted behindv saidlouver-ed panel and arranged to bemoved between open and closed limitsof adjustment, a damper control rod rotatably secured to one of said'panels, said control rod having a pair of opposite relatively wide surfaces bounded byza pair of opposite helical longitudinal edges, a'member 'of tough resilient plastic material secured to the other of said' panels andh'aving a slot whose edges receive and tightly grip-said relatively wide surfaces of the control rod, and means to rotate said control rod. 55 6 In combination an enclosure having a vent opening therein, a damper operable through a range between'topen and'closed limits relative to said opening, a damper control device mounted rotatably in said enclosure, and means secured to said damper and cooperating-With said control'device to operate said damper through said range, said damper control device including a long-pitch helicaledged portion and said cooperating means including'an apertured member of a'tough, resilient plastic gripping said long-pitch helical-edged portion, the thickness of 65 said plastic member measured along said helical-edged portion being only a small part of one-half the helical pitch.

7. In combination an enclosure having a vent opening therein, a damper operable through a range between open 70 and closed limits relative to said opening, a damper control device mounted rotatably in said enclosure,- and means secured to said damper and cooperating with said control device to operate said damper through said range, said damper control device including a long-pitch-helicaledged portion and said cooperating means including a.

tough, resilient plastic sheet disposed transverse to said helical-edged portion and said plastic sheet having a slot therein constituting a pair of relatively movable edges squeezed against opposite sides of said helical-edged portion.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN COMBINATION AN ENCLOSURE HAVING A FRONT PANEL HAVING AN APERTURED AREA, A DAMPER HINGED TO THE REAR OF SAID PANEL ADAPTED TO COVER SAID APERTURED AREA AND OPERABLE THROUGH AN ANGLE BETWEEN OPEN AND CLOSED LIMITS, A DAMPER CONTROL ROD HAVING OPPOSITE WIDE SURFACES BOUNDED BY HELICAL LONGITUDINAL EDGES, MEANS SUPPORTING SAID ROD FOR ROTATION ABOUT A FIXED AXIS, SAID SUPPORTING MEANS BEING CARRIED BY SAID FRONT PANEL, SAID MEANS ALSO CONSTRAINING THE ROD AGAINST AXIAL SHIFT RELATIVE TO SAID FRONT PANEL, AND A MEMBER OF TOUGH AND RESILIENT PLASTIC MATERIAL FIXED TO SAID DAMPER AND FORMED WITH AN ELONGATED SLOT GENERALLY PERPENDICULAR TO THE AXIS OF THE HINGED DAMPER, THE SLOT IN SAID PLASTIC MEMBER RECEIVING SAID DAMPER CONTROL ROD AND THE EDGES OF THE SLOT GRIPPING SAID OPPOSITE WIDE SURFACES OF THE CONTROL ROD, AND MEANS TO ROTATE SAID CONTROL ROD. 